The diversity of 1,020 Oryza glaberrima accessions conserved at the AfricaRice genebank was studied for its apparent amylose content (AAC) using the colorimetric determination method (AACC Method 61-03.01) and pasting viscosity properties using Rapid Visco Analyzer. We identified a subset of 406 accessions conserved at the AfricaRice Genebank for which the AAC ranged from intermediate (20-25%) to high (>25%) and pasting temperature from 86.4 to 95°C.

Apparent amylose content (AAC) of milled rice is one of the most important factors affecting the eating and cooking quality of rice grain. Cooked rice kernels with high AAC (>25%) are dry, separate, less tender, and become hard upon cooling, whereas those with low (10-20%) are glossy, soft, and sticky. Intermediate AAC (20-25%) rice is widely preferred since this kind of cooked rice is soft and flaky. The pasting properties, such as breakdown viscosity, setback viscosity, and final viscosity of starch are other factors that affect the eating and cooking quality of cooked rice and play an important role in selecting rice varieties. Good eating and cooking quality varieties usually have higher breakdown viscosity and lower setback viscosity and final viscosity. In contrast, inferior eating and cooking quality varieties commonly have lower breakdown viscosity and higher setback viscosity and final viscosity.